 The development of effective TB vaccines is crucial for global control of TB, but animal models do not always predict efficacy in humans. Recent clinical trials have shown promising results for three vaccine approaches, and experts suggest that alternative immune mechanisms such as donor unrestricted T cells, B lymphocytes, and antibodies may be potential correlates of protection. This article was authored by Claudio Cunupas, Jane Zaytrikas, and Warwick J. Britton.